The present invention relates to lacers for conveyor belts, and the like, and in particular to a belt lacer for wire hook lacings.
In wire hook lacings of the type disclosed in U.S. Pat. Nos. 1,393,451; 1,894,981; 1,498,275 and 1,768,935, the end of a conveyor belt, or the like, is positioned between a strip of belt connectors, which are still in their open configuration. Movement of the legs of the connectors toward one another is caused by the action of crimping jaws abutting the legs of the belt connectors, such that the belt connectors penetrate the belt with their pointed free ends, and are pressed between the crimping jaws on the whole. A disadvantage of previous pressing instruments or lacers is that the force is not optimally directed to the belt connectors, in particular the wire hooks. The consequence is that the forward, rounded area of the belt connector or wire hook, through which a rod is slid for positioning the belt connectors in the holding apparatus, is not U-shaped, but rather is more O-shaped in form. This inadequate or improper shaping of the belt connectors during pressing also leads to increased vibrations when the belt is running, as well as to increased wear on the belt connection.
In general, prior belt lacers function in conjunction with vises. The crimping jaws of the belt lacer are moved toward one another by closing the moveable jaw of the vise. Using a vise and its crimping jaws to create the force for closing the crimping jaws of the crimping jaw pair leads to the transfer of compressive force from the one crimping jaw of the crimping jaw pair that comes in contact with the moveable jaw of the vise, via the belt connectors or wire hooks and the resident conveyor belt, onto the other crimping jaw of the crimping jaw pair which lies against the stationary jaw of the vise instrument. These kinetics are in part responsible for the inadequate insertion or installation of the belt connectors and/or wire hooks into an associated conveyor belt.
DE 32 19 767 C2 discloses a device of the type referenced above. It serves to press in wire hooks via the use of a vise instrument. The device has a holding apparatus with a comb-shaped receptacle for the wire hooks. The holding apparatus is traversed by a mounting bolt in which the crimping jaws of the crimping jaw pair are mounted via slotted holes. The crimping jaws are pre-tensioned or biased toward their open configuration via springs. While in this open configuration, the device is suspended between the open jaws of the vise instrument from above. Upon closing the vise instrument, by shifting a movable jaw of the vise instrument in the direction of a stationary jaw, the crimping jaws of the device move toward one another, and the free ends of the wire hooks penetrate into the conveyor belt. Shortly before the maximal compressive force is introduced to the conveyor belt via the jaws of the vise instrument, the crimping jaws of the device move away from one another in the area of their slotted mounting holes. In order to bring this about, the pressure faces of the jaws of the vise instrument are not planar in design, but are slightly angled or bent. Hence, no conventional vise with planar pressure faces can be used for pressing in belt connectors. If a belt, potentially one of different thickness, must be fitted with wire hooks having an alternate design, it becomes necessary to use another device with comb-like slits that have an alternative design for the wire hooks. Hence, an existing device cannot be adapted to accommodate the new application.
One object of the present invention is to provide an improved device or belt lacer of the above-named type wherein the closing forces are optimally directed onto the belt connectors or wire hooks arranged on both sides of the belt when pressing the belt connectors or wire hooks into an associated belt. Moreover, the device has an uncomplicated design and a simple motion sequence during connector compression.
Another object is to provide the device or belt lacer with means for mandatory coupling of the rotational motions of the crimping jaws relative to the base element. Consequently, the crimping jaws are not freely moveable relative to the base element. Rather, the rotational motion of the crimping jaws occurs in synchronization relative to the base element. As such, the device is not dependent on the mode of operation of the force generating means that closes the crimping jaws. Consequently, it is insignificant whether one jaw of the vise instrument is stationary, while the other jaw is moveable, when using a vise instrument, for example. The mandatory coupling of the rotational motions of the crimping jaws results in transfer of the closing forces into the belt connectors or wire hooks through both crimping jaws, not just one. Mandatory coupling can be brought about in a particularly simple manner if the crimping jaws have rim gear sections that mesh with one another. The construction of a design such as this is particularly easy to achieve if the two crimping jaws are rotatably mounted in the base element about different rotational axes.
In order to optimize the connector pressing process, value should be placed on a simple relative motion of the crimping jaws. More specifically, it is preferred that the mounting of the crimping jaws occurs not by way of an undefined guidance of the slotted holes of the crimping jaws on mounting pins of the base element, but rather by providing a mounting that allows only a rotational motion of the crimping jaws about predetermined or assigned mounting axes on the base element.
In particular, in order to ensure that the tips of the belt connectors or wire hooks are pressed into the conveyor belt with optimal force, the respective crimping jaw is preferably of a two part construction. In particular, it has a lower jaw element mounted in a pivotal or swivel fashion in the base element, and a compressive jaw element connected to the lower jaw element and moveable relative to it, whereby the force generating means acts upon the compressive jaw element. At the beginning of the closing motion of the crimping jaw pair, the lower jaw element and the compressive jaw element should be positioned against one another, so that a precise motion of the crimping jaw is ensured. Not until the final phase of the pressing process, when it is primarily a matter of transferring the high compressive forces via the force generating means which close the crimping jaws of the crimping jaw pair onto the crimping jaws and from there onto the belt connectors, is the contact between compressive jaw element and lower jaw element lifted, since it is, by that point, merely a matter of the effect of the respective compressive jaw elements. The main compressive force of the respective compressive jaw element acts upon the penetration point of the belt connector or wire hook.
The pressing process can certainly be achieved by means of a vise instrument in which the opposing pressure surfaces of the jaws are arranged exclusively parallel to one another. According to a further advantageous embodiment, the force generating means for closing the crimping jaws may be constructed as components of a hydraulic press.
The return of the crimping jaws to their open position is achieved by relieving the force generating means for closing the crimping jaws, preferably via spring tension. Springs are also advantageously provided to maintain contact between the compressive jaw element and the lower jaw element, in particular tension springs.
The holding apparatus for the belt connectors preferably has comb-like slits for the belt connectors corresponding to the arrangement of the belt connectors. The belt connectors are able to be positioned in the holding apparatus in a defined fashion as a result of this comb-like formation. As it relates to wire hooks, the device is suitable for both cross wire mounted, as well as paper mounted variants of wire hooks. A pin is provided for holding together in generally known fashion the belt connectors that have been placed in the holding apparatus.
According to a particular embodiment of the invention, it is foreseen that the holding apparatus for the belt connectors and the base element comprise separate design elements. If belt connectors with alternate designs or configurations are to be pressed into a belt, in particular a belt of another thickness, it is consequently not necessary to replace the device with another device featuring an alternate spacing of the holding apparatus or comb-like slits, but rather only the holding apparatus for the belt connectors must be exchanged. This can be accomplished in especially simple fashion if the base element has a receptacle for sliding in the holding apparatus. In particular, the holding apparatus is held in the base element in form fitting fashion. More specifically, the holding apparatus is preferably capable of being slid into and within the base element in a direction parallel to the rotational axes of the crimping jaw pair. It is expedient for the length of the holding apparatus to be 1.5 to 2 times that of the extension of the crimping jaw pair in the longitudinal direction of the holding apparatus. It is in this regard that the slidability feature of the holding apparatus is to be seen. This feature makes it possible to successively advance the holding apparatus or the comb, and hence to always close only some of the belt connectors or wire hooks precisely and under high pressure. If the holding apparatus were not slidable, the compressive force would be distributed across the entire breadth of the holding apparatus or the comb, and consequently across many of the belt connectors placed in the holding apparatus.
Further features of the invention are presented in the description of the figures and in the figures themselves, whereby it is noted that all individual features and all combinations of individual features are essential to the invention.
These and other advantages of the invention will be further understood and appreciated by those skilled in the art by reference to the following written specification, claims and appended drawings.